There are a whole lot of reasons for Kyle Long to show up and impress in these rookie minicamps this year. It could be the fact that he's going to miss most (if not all) of the offseason training programs (up until training camp anyway). It could be that he's still a raw offensive lineman who only played offensive line for two seasons and registered all of four starts at guard in one season at the BCS level.
It could also be because he's been described as a quick learner who took an opportunity and ran with it all the way to the first round of the draft, and has to show why he was taken that high.
So it's good to hear that in the early parts of camp, Long's been drawing some good reviews regarding his growth and play.
Keep in mind of course that performing well at minicamp means about as much as holding a record on one of those Pop-a-Shot basketball arcade games, but any growth for a developmental player is a good sign, especially one like Long.